An infinite and eternal universe

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Two cosmological models involving the universe as never having had a beginning and never having an end (eternal), and having no boundaries (infinite) are really interesting me:

The Cyclic universe in which the universe has always been (for an infinite amount of time into the past) and always will (for an infinite time into the future) go through cycles of massive expansion and then contraction. Our Big Bang being the last bounce back from the previous contraction and the cosmic microwave background radiation (CMBR) the result of the rapid expansion from the last epoch.

The universe of dynamical equilibrium. The universe is not expanding. Redshift has been misunderstood - it is not down to the Doppler effect and Hubble himself never even stated that this was so, and treated that idea with skepticism/caution. The universe never had a beginning, it has always existed and always will (eternal) and is infinite in extent.

To me these models are more attractive because the Big Bang model I think was initially pushed by a Catholic priest (Lemaitre) so as to conveniently have the universe as having had a beginning and therefore very easy to argue that in order for there to be a beginning there would have had to have been a creator. I think big bang cosmological model was initiated to ensure a way to keep religious dogma within the scientific arena.

What are other people's thoughts on these two cosmological models? Has anyone seen any good mathematics to back them up? I think the Big Bang model is coming under more and more scrutiny these days - and rightly so. We don't want to have that one particular model become like a religious orthodoxy!

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The BBT is a consequence of extrapolating the cosmological expansion in reverse and it is what General Relativity describes but it loses validity as you approach the zero point. Basically, it's a limit of scientific knowledge and GR and not an actual boundary.

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the Big Bang model I think was initially pushed by a Catholic priest (Lemaitre) so as to conveniently have the universe as having had a beginning and therefore very easy to argue that in order for there to be a beginning there would have had to have been a creator. I think big bang cosmological model was initiated to ensure a way to keep religious dogma within the scientific arena.

Nonsense. It was proposed my several people, based on General Relativity. The astronomer and physicist Lemaitre used data (later known as Hubble's Law, and now as the Hubble-Laemaitre Law) to estimate the rate of expansion and age of the universe.

If it had been proposed purely for religious reasons then it would have been ignored or quickly abandoned. The reason it is still the accepted cosmological model is because of the evidence.

(Bizarrely, a lot of fundamental religions are opposed to the Big Bang model, possibly because it is based on relaitvity which they associate with moral relavitiy. But who know. It is hard to understand the motives of people that stupid.)

8 hours ago, ProximaCentauri said:

What are other people's thoughts on these two cosmological models? Has anyone seen any good mathematics to back them up? I think the Big Bang model is coming under more and more scrutiny these days - and rightly so. We don't want to have that one particular model become like a religious orthodoxy!

The Big Bang is a class of models based on the clear evidence that the universe is expanding and was, therefore, once much hotter and denser than now. There are multiple explanations for how it got into that hot dense state.

So the first of your models IS (a version of) the Big Bang. There is no evidence for that version of the model yet. Penrose has supported this model and claimed that there were patterns in the CMB that support it but this is not generally accepted (yet).

The second appears to pseudoscientific nonsense. I don't know where it comes from but does not appear to be consistent with any of the evidence.

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Nonsense. It was proposed my several people, based on General Relativity. The astronomer and physicist Lemaitre used data (later known as Hubble's Law, and now as the Hubble-Laemaitre Law) to estimate the rate of expansion and age of the universe.

If it had been proposed purely for religious reasons then it would have been ignored or quickly abandoned. The reason it is still the accepted cosmological model is because of the evidence.

(Bizarrely, a lot of fundamental religions are opposed to the Big Bang model, possibly because it is based on relaitvity which they associate with moral relavitiy. But who know. It is hard to understand the motives of people that stupid.)

The Big Bang is a class of models based on the clear evidence that the universe is expanding and was, therefore, once much hotter and denser than now. There are multiple explanations for how it got into that hot dense state.

So the first of your models IS (a version of) the Big Bang. There is no evidence for that version of the model yet. Penrose has supported this model and claimed that there were patterns in the CMB that support it but this is not generally accepted (yet).

The second appears to pseudoscientific nonsense. I don't know where it comes from but does not appear to be consistent with any of the evidence.

Penrose rejects the idea of inflation. I remember him saying during an interview "When inflation was first proposed [by Guth], I thought 'oh this thing isn't going to last five minutes!" and he went on to say that he is basically dumbfounded that so many have bought into inflation. The Cyclic universe model does not allow for inflation (Penrose's conformal cyclic cosmology model, anyway). Do you consider this to be psuedoscience, because it doesn't allow inflation? Also, he states there would never have been a first universe or first cycle and there will never be a final one. The cycle is infinite and eternal in both directions of time. This what the cyclic models tell us about the universe and they make much more scientific sense than the universe just coming about due to a quantum fluctuation in a vacuous state. This is of course my opinion and I accept that it is a dissenting one from the herd.

Edited April 7 by ProximaCentauri

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Penrose rejects the idea of inflation. I remember him saying during an interview "When inflation was first proposed [by Guth], I thought 'oh this thing isn't going to last five minutes!" and he went on to say that he is basically dumbfounded that so many have bought into inflation. The Cyclic universe model does not allow for inflation (Penrose's conformal cyclic cosmology model, anyway). Do you consider this to be psuedoscience, because it doesn't allow inflation?

Why would it be pseudoscience? Inflation and the cyclic universe are just two ways of explaining various aspects of the early universe: mainly the uniformity (the "horizon problem").

2 hours ago, ProximaCentauri said:

This what the cyclic models tell us about the universe and they make much more scientific sense than the universe just coming about due to a quantum fluctuation in a vacuous state.

Do you have scientific evidence in favour of one model over the other? Or is this just a personal preference for one model?

As far as I can tell, they both have the same amount of evidence; i.e. both are consistent with the existing evidence.

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….The Big Bang is a class of models based on the clear evidence that the universe is expanding and was, therefore, once much hotter and denser than now. There are multiple explanations for how it got into that hot dense state.

Right, so when a number of scientists on the show "How the Universe Works" say that the universe started "infinitely" small POINT, from a singularity, that is WRONG.

Nobody knows anything about "infinitely small." All anyone knows is the universe, that we can see, started from a hotter, denser state. We have no clue how large, or what shape, the big bang was at the earliest moments. It could have started from a huge, irregular shape from the very beginning. Nothing can be infinitely small.

Edited April 7 by Airbrush

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Whether infinitely old or infinitely vast makes no difference whatsoever.
Anything outside the observable universe, anything before the 'big bounce' or Planck era ( actually it should be inflationary era ), is causally disconnected from us.
We can never observe it, and it can never affect us in any way.

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To say that something is "infinitely" small is certainly an unfortunate mode of description. And meaningless unless it really means that its size is zero.

If we were to say that the mass of a photon is "infinitely small", we would make ourselves easy targets of ridicule. However, the mass of a photon is in reality not "infinitely small", rather it is identically zero. If we take "infinitely small", as a manner of speaking, to mean "of size zero", then we can all have a night of peaceful sleep. Except of course those who insist that nothing can be "infinitely small".

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To say that something is "infinitely" small is certainly an unfortunate mode of description. And meaningless unless it really means that its size is zero....

On a popular science program, "infinitely" small is just a figure of speech, not to be taken literally. I should have known.

As to the idea that the universe began from a "point" that was "infinitely small"...well it seems to me it could just as well started with a diameter of a googol light years, and was shaped like Crusty the Clown.

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On a popular science program, "infinitely" small is just a figure of speech, not to be taken literally. I should have known.

As to the idea that the universe began from a "point" that was "infinitely small"...well it seems to me it could just as well started with a diameter of a googol light years, and was shaped like crusty the clown.

On the other hand, if you look inside a black hole (don't go too close), then I suppose that mathematically, it has a point of size zero in its center which contains all its mass. Somehow the exact opposite of a photon, if you will. Whether this is absolutely a correct description or not of the reality or not, it could suggest why popular depictions of the big bang start from a very similar picture.

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To say that something is "infinitely" small is certainly an unfortunate mode of description. And meaningless unless it really means that its size is zero.

If we were to say that the mass of a photon is "infinitely small", we would make ourselves easy targets of ridicule. However, the mass of a photon is in reality not "infinitely small", rather it is identically zero. If we take "infinitely small", as a manner of speaking, to mean "of size zero", then we can all have a night of peaceful sleep. Except of course those who insist that nothing can be "infinitely small".

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What is the dimension of a point at the apex? Vanishingly small. It is not zero.

I only know Euclidean geometry and its various extensions that are locally Euclidean. The dimension of a point is zero here, and if you go to measure theory, then its size in terms of volume is zero as well.

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I only know Euclidean geometry and its various extensions that are locally Euclidean. The dimension of a point is zero here, and if you go to measure theory, then its size in terms of volume is zero as well.

Picture yourself travelling between two intersecting lines and yourself getting smaller in proportion as the lines get closer. When will you reach the end?

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Picture yourself travelling between two intersecting lines and yourself getting smaller in proportion as the lines get closer. When will you reach the end?

If I will not reach the end, then never. If I will, then, at whichever time that will be. So "vanishing", I get it now. At the end, if I reach it, I would have vanished to zero. But I am not sure that your image tells us much about places that are "infinitely small".

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If I will not reach the end, then never. If I will, then, at whichever time that will be. So "vanishing", I get it now. At the end, if I reach it, I would have vanished to zero. But I am not sure that your image tells us much about places that are "infinitely small".

The visualization problem is the same as infinitely big. At the end of the day, it's a problem with the model in question.

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The visualization problem is the same as infinitely big. At the end of the day, it's a problem with the model in question.

Sure, it depends on the theory you want to engage. A unit line segment has volume zero in the Euclidean plane, and measure one on the real line, and it has cardinality \(2^{\aleph_0}\) as a set of points in the real plane.

Edited April 7 by taeto

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A point is, by definition, dimensionless, and without extent.
The early universe, even at Planck scale, might not have applicable spatial and a temporal dimension, but it would still have an extent.
( just an extensive, non-causal quantum foam )

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A point is, by definition, dimensionless, and without extent.
The early universe, even at Planck scale, might not have applicable spatial and a temporal dimension, but it would still have an extent.
( just an extensive, non-causal quantum foam )

So no way the early universe in its hot, dense state at the very moment of the (supposed) Big Bang could have been infinite at a quantum level? (Eternal) inflation caused infinite expansion? Can you please elaborate?

I think the universe has either always been infinite in extent at all sizes or it has not.

On 4/7/2020 at 1:36 PM, Strange said:

Why would it be pseudoscience? Inflation and the cyclic universe are just two ways of explaining various aspects of the early universe: mainly the uniformity (the "horizon problem").

Do you have scientific evidence in favour of one model over the other? Or is this just a personal preference for one model?

As far as I can tell, they both have the same amount of evidence; i.e. both are consistent with the existing evidence.

I have no scientific evidence in favour of one model over the other. I'm just a lay person with an interest in cosmology, but I trust wizard mathematicians like Penrose who have shifted in their views from believing in the standard Big Bang cosmological model and come up with something which is far superior, the Conformal Cyclic Cosmology (CCC).

CCC is treated with ridicule by the herd, and Penrose is treated like a heretic in the scientific community for dissenting from the mainstream almost religious-like orthodoxy - since he no longer bows down to the standard cosmological model which places the Big Bang as the beginning of this universe - with the question of what came before deemed a 'silly question to ask'.

I saw a video in which Sean Carroll became very upset - you could see from the look on his face - when Penrose basically dared to rubbish inflation for the absurd idea it is. He was denounced of course, as you may expect, by an emotional Carroll committed to the standard model orthodoxy.

I always pay more attention to the dissenters who once were with the herd and held the mainstream consensus. Because they're usually on to something.

Though I am not a mathematician and will not pretend to understand any of the maths behind CCC , but I trust someone like Penrose when he says he never liked inflation and that the standard model is wrong. So this is why I believe in the cyclic universe or CCC model which says that the universe is not only infinite in extent and in its expansion, but is eternal - there will never be an end to the universe ; there will never be a final 'cycle'. And there was never a first one, either - which is hard to get our heads around, but the universe doesn't care about that. Not being able to understand how the universe could have had no beginning (or rather how there could have been no first cycle) won't make the universe change to suit what we would rather want just so it's easier for us to understand.

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Is it? Scientists can be very critical of other's theories, but I am not aware that this is treated especially badly.

43 minutes ago, ProximaCentauri said:

and Penrose is treated like a heretic in the scientific community

I don't believe you.

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for dissenting from the mainstream almost religious-like orthodoxy

There is no religious-like orthodoxy.

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since he no longer bows down to the standard cosmological model which places the Big Bang as the beginning of this universe

Cyclic universe models are Big Bang models. They are based on the universe expanding from a hot dense state; i.e. the Big Bang model.

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with the question of what came before deemed a 'silly question to ask'.

There are many different attempts to question what happened before the notional Big Bang event (which may never have happened).

46 minutes ago, ProximaCentauri said:

Though I am not a mathematician and will not pretend to understand any of the maths behind CCC , but I trust someone like Penrose when he says he never liked inflation and that the standard model is wrong.

Lots of people don't like inflation much. Including Steinhardt who did a lot of the original work on the idea. There are lots of alternative hypotheses. It is very difficult to find evidence for any of them.

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So this is why I believe in thecyclic universeor CCC model which says that the universe is not onlyinfinite in extentand in its expansion, but is eternal - there willnever be an endto the universe ; there will never be a final 'cycle'. And there wasnever a first one, either - which is hard to get our heads around, but the universe doesn't care about that. Not being able to understand how the universe could have hadno beginning(or rather how there could have been no first cycle) won't make the universe change to suit what we would ratherwantjust so it's easier for us tounderstand.

Science is not about beliefs, but about evidence. Penrose claimed that there was evidence for this model in patterns in the CMB, but this has not been confirmed.

There are other models that avoid inflation, such as the universe being infinitely old in a meta-stable state before expansion started. But there is no solid evidence for them either yet.

So the rational position is to say "we don't know" and hope for some evidence one way or another.

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Every physics theory has competitive theories this is true of inflation. The CMB itself is supportive evidence through big bang nucleosynthesis of the BB.

One of the difficult things to explain is how the supercooling due to rapid expansion and reheating due to the inflation slow roll leads to the metalicity values measured at z=1090. When you get right down to it the percentages match those predicted by inflation and quite frankly limit the range of viable inflation models.

So it really doesn't matter what one believes.

The only thing that matters is what observational evidence tells us.

If you want a listing of viable inflation models that match observational evidence (though the last update was 2013.) See here